Traditionally electronic chassis are made from multiple forms of aluminum that surround circuit boards that contain RF, microwave, millimeter wave, or high speed digital circuitry. The chassis is designed to prevent internally generated radiation from escaping outside of the chassis and external radiation from entering the chassis. Aluminum does not damp electromagnetic resonances within a cavity (a lossy material must be added) and does not provide magnetic shielding. Aluminum has a high thermal conductivity and provides means for the removal of excess heat. Machining a chassis from aluminum is an expensive manufacturing process.
The demands by aerospace customers for weight and cost reductions and simpler operation (eliminate convective cooling) open up the opportunity for novel composite materials, structures, and manufacturing processes to replace traditional materials, particularly aluminum shaped by machining. Composites can achieve a 20-50% (typical 30%) weight reduction compared to aluminum but must also match certain very desirable properties of aluminum: high electrical conductivity, high thermal conductivity and low raw material costs. However, hand layup of composites is expensive, even compared to machined aluminum, so inexpensive manufacturing methods are needed.